Acoustic impedance tests. Medical search

Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of sound flow through the middle ear. These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural muscle reflex elicitation). This term is used also for various components of impedance and admittance (e.g., compliance, conductance, reactance, resistance, susceptance).

The branch of physics that deals with sound and sound waves. In medicine it is often applied in procedures in speech and hearing studies. With regard to the environment, it refers to the characteristics of a room, auditorium, theatre, building, etc. that determines the audibility or fidelity of sounds in it. (From Random House Unabridged Dictionary, 2d ed)

Any device or element which converts an input signal into an output signal of a different form. Examples include the microphone, phonographic pickup, loudspeaker, barometer, photoelectric cell, automobile horn, doorbell, and underwater sound transducer. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)

The resistance to the flow of either alternating or direct electrical current.

The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.

Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (Stedman, 25th ed)

A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. It is used principally to calculate stroke volume and cardiac volume, but it is also related to myocardial contractility, thoracic fluid content, and circulation to the extremities.

A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.

Conditions that impair the transmission of auditory impulses and information from the level of the ear to the temporal cortices, including the sensorineural pathways.

Radiographic examination of the process of defecation after the instillation of a CONTRAST MEDIA into the rectum.

Former members of the armed services.

Intra-aural contraction of tensor tympani and stapedius in response to sound.

A general term for the complete or partial loss of the ability to hear from one or both ears.

The testing of the acuity of the sense of hearing to determine the thresholds of the lowest intensity levels at which an individual can hear a set of tones. The frequencies between 125 and 8000 Hz are used to test air conduction thresholds and the frequencies between 250 and 4000 Hz are used to test bone conduction thresholds.

The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.

A short muscle that arises from the pharyngotympanic tube (EUSTACHIAN TUBE) and inserts into the handle of the MALLEUS. This muscle pulls the handle medially thus controlling the tension and movement of TYMPANIC MEMBRANE.

A tiny muscle that arises from the posterior wall of the TYMPANIC CAVITY of MIDDLE EAR with its tendon inserted onto the neck of the STAPES. Stapedius pulls the stapes posteriorly and controls its movement.

An abnormally disproportionate increase in the sensation of loudness in response to auditory stimuli of normal volume. COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; FACIAL NERVE DISEASES; STAPES SURGERY; and other disorders may be associated with this condition.

A mobile chain of three small bones (INCUS; MALLEUS; STAPES) in the TYMPANIC CAVITY between the TYMPANIC MEMBRANE and the oval window on the wall of INNER EAR. Sound waves are converted to vibration by the tympanic membrane then transmitted via these ear ossicles to the inner ear.

A branch of the facial (7th cranial) nerve which passes through the middle ear and continues through the petrotympanic fissure. The chorda tympani nerve carries taste sensation from the anterior two-thirds of the tongue and conveys parasympathetic efferents to the salivary glands.

An oval semitransparent membrane separating the external EAR CANAL from the tympanic cavity (EAR, MIDDLE). It contains three layers: the skin of the external ear canal; the core of radially and circularly arranged collagen fibers; and the MUCOSA of the middle ear.

The lower chamber of the COCHLEA, extending from the round window to the helicotrema (the opening at the apex that connects the PERILYMPH-filled spaces of scala tympani and SCALA VESTIBULI).

A characteristic symptom complex.

A chromosome disorder associated either with an extra chromosome 21 or an effective trisomy for chromosome 21. Clinical manifestations include hypotonia, short stature, brachycephaly, upslanting palpebral fissures, epicanthus, Brushfield spots on the iris, protruding tongue, small ears, short, broad hands, fifth finger clinodactyly, Simian crease, and moderate to severe INTELLECTUAL DISABILITY. Cardiac and gastrointestinal malformations, a marked increase in the incidence of LEUKEMIA, and the early onset of ALZHEIMER DISEASE are also associated with this condition. Pathologic features include the development of NEUROFIBRILLARY TANGLES in neurons and the deposition of AMYLOID BETA-PROTEIN, similar to the pathology of ALZHEIMER DISEASE. (Menkes, Textbook of Child Neurology, 5th ed, p213)

A cluster of metabolic risk factors for CARDIOVASCULAR DISEASES and TYPE 2 DIABETES MELLITUS. The major components of metabolic syndrome X include excess ABDOMINAL FAT; atherogenic DYSLIPIDEMIA; HYPERTENSION; HYPERGLYCEMIA; INSULIN RESISTANCE; a proinflammatory state; and a prothrombotic (THROMBOSIS) state. (from AHA/NHLBI/ADA Conference Proceedings, Circulation 2004; 109:551-556)

A condition characterized by severe PROTEINURIA, greater than 3.5 g/day in an average adult. The substantial loss of protein in the urine results in complications such as HYPOPROTEINEMIA; generalized EDEMA; HYPERTENSION; and HYPERLIPIDEMIAS. Diseases associated with nephrotic syndrome generally cause chronic kidney dysfunction.

Chronic inflammatory and autoimmune disease in which the salivary and lacrimal glands undergo progressive destruction by lymphocytes and plasma cells resulting in decreased production of saliva and tears. The primary form, often called sicca syndrome, involves both KERATOCONJUNCTIVITIS SICCA and XEROSTOMIA. The secondary form includes, in addition, the presence of a connective tissue disease, usually rheumatoid arthritis.

A syndrome of defective gonadal development in phenotypic females associated with the karyotype 45,X (or 45,XO). Patients generally are of short stature with undifferentiated GONADS (streak gonads), SEXUAL INFANTILISM, HYPOGONADISM, webbing of the neck, cubitus valgus, elevated GONADOTROPINS, decreased ESTRADIOL level in blood, and CONGENITAL HEART DEFECTS. NOONAN SYNDROME (also called Pseudo-Turner Syndrome and Male Turner Syndrome) resembles this disorder; however, it occurs in males and females with a normal karyotype and is inherited as an autosomal dominant.

Software used to locate data or information stored in machine-readable form locally or at a distance such as an INTERNET site.

Organized activities related to the storage, location, search, and retrieval of information.

A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.

A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.

The portion of an interactive computer program that issues messages to and receives commands from a user.

Sequential operating programs and data which instruct the functioning of a digital computer.

A fine channel that passes through the TEMPORAL BONE near the SCALA TYMPANI (the basilar turn of the cochlea). The cochlear aqueduct connects the PERILYMPH-filled bony labyrinth to the SUBARACHNOID SPACE.

Failure in built environment with loss of functional integrity.

Manometric pressure of the CEREBROSPINAL FLUID as measured by lumbar, cerebroventricular, or cisternal puncture. Within the cranial cavity it is called INTRACRANIAL PRESSURE.

A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

The fluid of the body that is outside of CELLS. It is the external environment for the cells.

A genus of gram-negative, rod-shaped, gliding bacteria in the family XANTHOMONADACEAE. Strongly proteolytic, it is involved in lysing a variety of microorganisms.

Method of measuring and mapping the scope of vision, from central to peripheral of each eye.

The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.

The total area or space visible in a person's peripheral vision with the eye looking straightforward.

An autosomal recessive inherited disorder with multiple forms of phenotypic expression, caused by a defect in the oxidative decarboxylation of branched-chain amino acids (AMINO ACIDS, BRANCHED-CHAIN). These metabolites accumulate in body fluids and render a "maple syrup" odor. The disease is divided into classic, intermediate, intermittent, and thiamine responsive subtypes. The classic form presents in the first week of life with ketoacidosis, hypoglycemia, emesis, neonatal seizures, and hypertonia. The intermediate and intermittent forms present in childhood or later with acute episodes of ataxia and vomiting. (From Adams et al., Principles of Neurology, 6th ed, p936)

A product of hard secondary xylem composed of CELLULOSE, hemicellulose, and LIGNANS, that is under the bark of trees and shrubs. It is used in construction and as a source of CHARCOAL and many other products.

A plant genus of the family ACERACEAE, best known for trees with palmately lobed leaves.

Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.

The structure that forms the roof of the mouth. It consists of the anterior hard palate (PALATE, HARD) and the posterior soft palate (PALATE, SOFT).

Recording of information on magnetic or punched paper tape.

Confirmation of deafness in infancy. (1/154)

AIM: To assess delay in confirming hearing impairment in infants identified by universal neonatal screening and to investigate the causes. PATIENTS: Infants identified from 25 199 babies screened from January 1992 to December 1997. METHODS: A two stage transient evoked oto-acoustic emission test (TEOAE), with a threshold auditory brainstem response (ABR) recording undertaken on those who failed. The screen identified infants with a permanent congenital hearing impairment (PCHI) averaging 40 dBnHL or worse in the best ear. Those with less impairment were also ascertained. The positive predictive value (PPV) of the ABR test and measures of delay between identification and eventual diagnosis were analysed. RESULTS: A targeted PCHI was found in 1.18/1000 neonates. The PPV of the ABR for confirming a targeted PCHI was 100% when the ABR threshold was >/= 80 dBnHL. Nine of 11 infants with this threshold had severe or profound permanent deafness. The delay from ABR to audiological certainty was about 1 month-diagnosis was confirmed around 3 months. There was uncertainty when the ABR was 40-80 dBnHL. The PPV was 60% and 8% when the ABR thresholds were 70 dBnHL and 50 dBnHL, respectively. 85 of 111 infants with ABR thresholds in this range had a temporary conductive impairment. Their early diagnosis depended upon the type and degree of hearing impairment and diagnosis was delayed to about 8 months in these infants. CONCLUSIONS: Hearing impairments identified by universal screening are delayed in all but those with severe or profound bilateral PCHI. This delay can be reduced by applying in early infancy a battery of audiological tests and requires further exploration. (+info)

Otolaryngological findings in congenital nasolacrimal duct obstruction and implications for prognosis. (2/154)

AIM: To investigate otolaryngological abnormalities associated with congenital nasolacrimal duct obstruction (CNLDO) and their effect on the prognosis. METHODS: 65 consecutive cases of CNLDO were followed up with routine otorhinolaryngological examination with tympanometry. RESULTS: Otitis media with effusion (OME) and uvula bifida were detected in 44.6% and 9.2% of the children, respectively. Medical treatment and probing were less effective in patients with OME (p<0. 05). CONCLUSIONS: OME and uvula bifida are significant anomalies associated with CNLDO and the former has a marked effect on the prognosis. This finding may help to determine the patients who will need further treatment after massage and probing. (+info)

Tympanometry for diagnosis and treatment of otitis media in general practice. (3/154)

OBJECTIVE: The aim of this study was to evaluate the role of tympanometry for diagnosis, treatment and follow-up of otitis media in general practice. METHODS: The results from otoscopy performed by 40 physicians in general practice in Vejle County, Denmark were combined with the clinical condition and this was recorded as the preliminary decision about diagnosis, treatment and follow-up. Subsequently, tympanometry was performed in 3176 children aged between 1 month and 16 years; a total of 6352 tympanometries. With this added knowledge, a final decision about diagnosis, treatment and follow-up was recorded. The practitioners were trained in performing tympanometry including the interpretation of the results. Simultaneously, they were involved in the establishment of guidelines for diagnosis, treatment and follow-up of otitis media in general practice. The main outcome measures were changes between preliminary and final decisions about diagnoses, treatments and follow-up regimens. RESULTS: Tympanometry was performed successfully in 87.7% of the children, and in 26.4% changes in diagnoses were found. However, tympanometry did not influence the distributions of the main outcome measures in the sample as a whole. Uncomplicated cases were checked in general practice and referrals to specialists were not increased. CONCLUSION: Tympanometry can be performed successfully in general practice after appropriate instruction. In 26.4% of children, the diagnoses were changed, which may result in more appropriate treatment and follow-up. Tympanometry is a clinically relevant supplement to the examination of a child in general practice. (+info)

Behaviour and developmental effects of otitis media with effusion into the teens. (4/154)

OBJECTIVE: To examine whether behavioural or cognitive sequelae of otitis media with effusion (OME) continue into late childhood and the early teens (11-18 years). SETTING: Data from a large multipurpose birth cohort study: the Dunedin multidisciplinary health and development study. PARTICIPANTS: Around 1000 children from the study. The main independent variable of interest was otological status of the child up to age 9. MAIN OUTCOME MEASURES: Parent and teacher rated behaviour problems, including antisocial, neurotic, hyperactive, and inattentive behaviours, and tests of academic achievement including intelligence quotient (IQ), reading, and spelling were available in a high proportion of the cohort at ages 11 to 18 years. RESULTS: After adjustments for covariates such as socioeconomic status, hyperactive and inattentive behaviour problems were evident as late as 15 years, and lower IQ associated with OME remained significant to 13 years. The largest effects were observed for deficits in reading ability between 11 and 18 years. CONCLUSIONS: No previous study considering behaviour problems as an outcome has followed children long enough to determine whether some of the early sequelae of OME are still present in the early to late teens. Some developmental sequelae of OME, particularly deficits in reading ability, can persist into late childhood and the early teens. (+info)

Does early detection of otitis media with effusion prevent delayed language development? (5/154)

OBJECTIVE: To consider whether earlier detection of otitis media with effusion (OME) in asymptomatic children in the first 4 years of life prevents delayed language development. METHODS: MEDLINE and other databases were searched and relevant references from articles reviewed. Critical appraisal and consensus development were in accordance with the methods of the Canadian Task Force on Preventive Health Care. RESULTS: No randomised controlled trials assessing the overall screening for OME and early intervention to prevent delay in acquiring language were identified, although one trial evaluated treatment in a screened population and found no benefit. The "analytic pathway" approach was therefore used, where evidence is evaluated for individual steps in a screening process. The evidence supporting the use of tools for early detection such as tympanometry, microtympanometry, acoustic reflectometry, and pneumatic otoscopy in the first 4 years of life is unclear. Some treatments (mucolytics, antibiotics, steroids) resulted in the short term resolution of effusions as measured by tympanometry. Ventilation tubes resolved effusions and improved hearing. Ventilation tubes in children with hearing loss associated with OME benefited children in the short term, but after 18 months there was no difference in comparison with those assigned to watchful waiting. Most prospective cohort studies that evaluated the association between OME and language development lacked adequate measurement of exposure or outcome, or suffered from attrition bias. Findings with regard to the association were inconsistent. CONCLUSIONS: There is insufficient evidence to support attempts at early detection of OME in the first 4 years of life in the asymptomatic child to prevent delayed language development. (+info)

Auditory system: Peripheral nonlinearity and central additivity, as revealed in the human stapedius-muscle reflex. (6/154)

Human stapedius-muscle contractions in response to 3-kHz, 20-msec tone bursts were determined indirectly by measuring the associated acoustic-impedance changes at the tympanic membrane with an acoustic bridge. The measurement was possible because the bridge practically eliminates the effect of the ear-canal air volume interposed between the tympanic membrane and the tip of the measuring tube. By using burst pairs, temporal additivity of the muscle responses was demonstrated both when the stimulus bursts were presented contralaterally to the measured impedance changes and when the first burst was presented ipsilaterally. The summation time constant was on the order of 200 msec, much longer than the twitch time constant of the muscle fibers. Therefore, the summation had to take place in a nucleus preceding the stapedius muscle. The magnitude of the muscle response obeyed a compressive function paralleling the loudness function up to sound pressure levels of at least 120 dB. (+info)

Practical screening priorities for hearing impairment among children in developing countries. (7/154)

Routine screening for hearing impairment in childhood is now widespread in industrial countries, although there is considerable controversy over the most efficient techniques and procedures. In most developing countries, however, routine screening programmes for hearing impairment do not currently exist. The problems involved in implementing screening programmes in developing and industrial countries are very different, and in selecting screening procedures for a particular population the following factors have to be taken into consideration: the environmental test conditions; the availability of resources for equipment and the training of testers; the local attitudes towards disability; the level of hearing impairment that may cause handicaps; and the major types of pathology causing hearing impairment. We suggest that in developing countries children should be screened at school entry using a simple field audiometer and that the external ear be inspected for the presence of a discharge. There is an urgent need to develop reliable and simple screening procedures for infants and young children; where possible, all children should be screened for severe or significant hearing impairment before the age of 2 years. No screening should, however, be implemented until appropriate follow-up services are available. (+info)

Impedance analysis of the organ of corti with magnetically actuated probes. (8/154)

An innovative method is presented to measure the mechanical driving point impedance of biological structures up to at least 40 kHz. The technique employs an atomic force cantilever with a ferromagnetic coating and an external magnetic field to apply a calibrated force to the cantilever. Measurement of the resulting cantilever velocity using a laser Doppler vibrometer yields the impedance. A key feature of the method is that it permits measurements for biological tissue in physiological solutions. The method was applied to measure the point impedance of the organ of Corti in situ, to elucidate the biophysical basis of cochlear amplification. The basilar membrane was mechanically clamped at its tympanic surface and the measurements conducted at different radial positions on the reticular lamina. The tectorial membrane was removed. The impedance was described by a generalized Voigt-Kelvin viscoelastic model, in which the stiffness was real-valued and independent of frequency, but the viscosity was complex-valued with positive real part, which was dependent on frequency and negative imaginary part, which was independent of frequency. There was no evidence for an inertial component. The magnitude of the impedance was greatest at the tunnel of Corti, and decreased monotonically in each of the radial directions. In the absence of inertia, the mechanical load on the outer hair cells causes their electromotile displacement responses to be reduced by only 10-fold over the entire range of auditory frequencies. (+info)

Acoustic impedance of the embouchure hole appears the most critical parameter. Critical variables affecting this acoustic ... Finding a particularly good example of a flute is dependent on play-testing. Head joint upgrades are usually suggested as a way ... "Acoustic impedance of the flute". Flute acoustics: an introduction. "Curved Head Student Flute by Gear4music". Gear4music. 2016 ... However, small deviations from the objective 'mechanical' pitch (which is related to acoustic impedance of a given fingering) ...

https://en.wikipedia.org/wiki/Western_concert_flute

... but which is at a high acoustic pressure (thus a very high acoustic impedance), is partly converted into audible sound in air ... This is most commonly done with two exams called the Weber test and Rinne test, respectively. Lower-pitched ones, usually at ... If just held in open air, the sound of a tuning fork is very faint due to the acoustic impedance mismatch between the steel and ... thus low acoustic impedance). The pitch of a tuning fork can also be heard directly through bone conduction, by pressing the ...

https://en.wikipedia.org/wiki/Tuning_fork

It was found that a layer with high acoustic impedance with a backing of a softer, low acoustic impedance layer (such as low ... Bass et al., 2006, Comparative testing of effectiveness of different helmet/shield designs at reducing head acceleration due to ... similar to the NIJ standards that are widely used to test and compare body armor or materials used to stop ballistic threats. ... it was also shown that it is important to understand the frequency content of the applied blast wave and to experimentally test ...

https://en.wikipedia.org/wiki/Bomb_suit

... noise and vibration testing and structural dynamics testing. Brüel & Kjær offers products covering a wide range of acoustic ... and acoustic panel in situ impedance measurement) It also supplies in-flight engine monitoring with flight-certified, high- ... Other systems have tested Astrium's satellite prior to launch, and performed qualification and acceptance testing, such as the ... These ensure the quality of new lighter material applications by modal testing and improving the quality and test efficiency in ...

https://en.wikipedia.org/wiki/Brüel_&_Kjær

... is made of a material having a low acoustic impedance and has a sufficiently thick wall to ensure structural stability. Close- ... Test frequencies ranged from 0.5 Hz to 40 Hz. Test subjects suffered motor ataxia, nausea, visual disturbance, degraded task ... In the proposed test, test parameters will be sensitivity, background noise, signal fidelity (harmonic distortion), and ... These tests are assumed by researchers to be the nucleus of the current urban myth. The report "A Review of Published Research ...

https://en.wikipedia.org/wiki/Infrasound

... can be sometimes used as replacement for water in ultrasonic testing, as it has favourably higher acoustic impedance ( ... Further testing on this subject was abandoned due to the unexpected results, as this was not the goal of the experiment. ... reagent.co.uk Acoustic Properties for Liquids. nde-ed.org Formula E uses pollution-free glycerine to charge cars. fiaformulae. ... Glycerol injections can be used as a simple test for liver damage, as its rate of absorption by the liver is considered an ...

https://en.wikipedia.org/wiki/Glycerol

CSSI transforms seismic data to a pseudo-acoustic impedance log at every trace. Acoustic impedance is used to produce more ... which can then be narrowed through testing for best fit against various measurements (including production data). An example of ... The inversion results in acoustic impedance (AI), which is the product of rock density and p-wave velocity. Unlike seismic ... A good (CSSI) algorithm will produce four high-quality acoustic impedance volumes from full or post-stack seismic data: full- ...

https://en.wikipedia.org/wiki/Seismic_inversion

... the use of some type of acoustic coupling medium in order to efficiently transmit the energy from the sensor to the test ... piezoelectric transducer can produce frequencies in the MHz that can easily propagate through even high acoustic impedance ... Non-contact ultrasound (NCU) is a method of non-destructive testing where ultrasound is generated and used to test materials ... However in non-contact ultrasound, ambient air is the only acoustic coupling medium. An electromagnetic acoustic transducer ( ...

https://en.wikipedia.org/wiki/Non-contact_ultrasound

The acoustic (or seismic) impedance, Z, is defined by the equation: Z = v ρ {\displaystyle Z=v\rho \ } , where v is the seismic ... The first field tests were conducted near Oklahoma City, Oklahoma in 1921. Early reflection seismology was viewed with ... Seismic waves are mechanical perturbations that travel in the Earth at a speed governed by the acoustic impedance of the medium ... Hydrocarbon exploration - used by the hydrocarbon industry to provide a high resolution map of acoustic impedance contrasts at ...

https://en.wikipedia.org/wiki/Reflection_seismology

Moreover, the acoustic performance is linked to the acoustic impedance which can be measured with one of the following ... The acoustic liners' performance can be verified in dedicated experimental test rigs, by means of virtual prototypes or by ... Effects of liner geometry on acoustic impedance. AIAA Paper, 2446, 2002. Dean, P. D.,An In-Situ Method of Wall Acoustic ... Moreover, the in-situ method is the only one able to measure the impedance directly on full scale acoustic liners. Murray, P., ...

https://en.wikipedia.org/wiki/Acoustic_liner

A key factor for acoustic band gap engineering is the impedance mismatch between periodic elements comprising the crystal and ... The first successful industrial applications of acoustic metamaterials were tested for aircraft insulation. Properties of ... This concept can be exploited with periodic arrangements of impedance-mismatched elements to affect acoustic waves in the ... With acoustic metamaterials the direction of sound through the medium can be controlled by manipulating the acoustic refractive ...

https://en.wikipedia.org/wiki/Acoustic_metamaterial

The test is carried out by generating an acoustic pulse from a speaker or spark source and this sound pulse is transmitted to ... is reflected back to a microphone and this reflection is generated according to the changes in the local acoustic impedance ... O, Hilberg; AC, Jackson; DL, Swift; OF, Pedersen (1989). "Acoustic Rhinomtry: Evaluation of nasal cavity geometry by acoustic ... Acoustic rhinometry is a diagnostic measurement of cross sectional area and length of the nose and the nasal cavity through ...

https://en.wikipedia.org/wiki/Acoustic_rhinometry

The Acoustic Test Tank is equipped with the instrumentation required for determining the acoustic characteristics of sonar ... devices designed for frequency response calibrations, radiation pattern plots, and impedance and admittance characterizations. ... Laboratory which houses an array of tanks including an Acoustic Reverberant Tank and an Acoustic Test Tank for acoustic ... ARL operates the Advanced Nuclear Fuel Test Facility (ANFTF) which is a Westinghouse-funded facility to test advanced power ...

https://en.wikipedia.org/wiki/Pennsylvania_State_University_Applied_Research_Laboratory

Common causes of echo include impedance mismatches in analog circuitry and an acoustic path from the receive to transmit signal ... "Performance and Stress Testing of SIP Servers, Clients and IP Networks". StarTrinity. August 13, 2016. "Testing Voice over IP ( ... The metrics are determined by VoIP performance testing and monitoring. A VoIP media gateway controller (aka Class 5 Softswitch ... "Methodology for SIP Infrastructure Performance Testing" (PDF). Miroslav Voznak, Jan Rozhon. August 14, 2016. "Voice over IP ( ...

https://en.wikipedia.org/wiki/Voice_over_IP

An acoustic interferometer is an instrument for measuring the physical characteristics of sound waves in a gas or liquid, such ... It is also used in the testing of optical components. In 1946, a technique called astronomical interferometry was developed. ... velocity, wavelength, absorption, or impedance. A vibrating crystal creates ultrasonic waves that are radiated into the medium ... Interference effects can be observed with all types of waves, for example, light, radio, acoustic, surface water waves, gravity ...

https://en.wikipedia.org/wiki/Wave_interference

When a wave encounters a change in acoustic impedance, such as hitting a solid surface, acoustic reflections transpire. These ... "Fire Testing Data". auralex.com. Chen, Francine Robina (1980). "Acoustic characteristics and intelligibility of clear and ... Foley, Dennis (2020-02-05). "How Does Acoustic Foam Work?". Acoustic Fields. Retrieved 2020-12-31. "What Is Acoustic Foam Made ... Many acoustic foam products are treated with dyes and/or fire retardants. The objective of acoustic foam is to improve or ...

https://en.wikipedia.org/wiki/Acoustic_foam

A hydrophone can detect airborne sounds, but will be insensitive because it is designed to match the acoustic impedance of ... Bragg tested a hydrophone from a captured German U-boat and found it inferior to British models. By the end of the war, the ... the high acoustic impedance of piezoelectric materials facilitated their use as underwater transducers. The same piezoelectric ... but will give poor performance due to the similarly bad acoustic impedance match. The first hydrophones consisted of a tube ...

https://en.wikipedia.org/wiki/Hydrophone

These boards were wired at the factory, tested and packaged with the unassembled chassis. It remained only for the consumer to ... The resistant venting action lowered the "Q" of the system and reduced impedance variation near resonance in the A-Series ... whose acoustic resistance is very carefully controlled. ... tested circuit boards that only required the customer to wire ... which generally required the purchaser to assemble and test the PC boards themselves, a relatively precise and time-consuming ...

https://en.wikipedia.org/wiki/Dynaco

... which reflect the sound due to mismatched acoustic impedance. Ultrasound weapons are much more effective underwater than ... Tests performed on mice show the threshold for both lung and liver damage occurs at about 184 dB. Damage increases rapidly as ... Long Range Acoustic Device Brown note Sone (a unit of loudness of sound) Sound pressure Sound energy flux Sound power Sound ... The Long Range Acoustic Device (LRAD) produces a 30 degree cone of audible sound in frequencies within the human hearing ...

https://en.wikipedia.org/wiki/Sonic_weapon

... allowing the acoustic transfer impedance Z a c {\displaystyle Z_{ac}} to be easily modelled. One of the microphones is then ... This service is offered by some microphone manufacturers and by independent testing laboratories. Microphone calibration by ... and the acoustical transfer impedance equals the electrical transfer impedance. Z i j = U j I i = M i Z a c M j {\displaystyle ... is determined during the calibration procedure by measuring the current and voltage and the acoustic transfer impedance depends ...

https://en.wikipedia.org/wiki/Measurement_microphone_calibration

Most of the time, the stapedius reflex is tested with tympanometry. The contraction of the stapedius muscle stiffens the middle ... 267-9. ISBN 978-0-07-285293-6. "Impedance Audiometry". MedScape. 2018-09-12. W. Niemeyer (1971). "Relations between the ... the sound used to trigger the acoustic reflex). For most animals, the acoustic reflex is the contraction of both middle ear ... The acoustic reflex threshold (ART) is the sound pressure level (SPL) from which a sound stimulus with a given frequency will ...

https://en.wikipedia.org/wiki/Acoustic_reflex

Anechoic Chamber: another acoustic test facility Echo chamber: a reverberation room used for music recording Electromagnetic ... The change of impedance (compared to the air) these surfaces present to incident sound is so large that virtually all of the ... an electromagnetic environment mainly for Electromagnetic Compatibility testing ISO Standard for Measurement of Acoustic ... additional acoustic diffusers are often used to create more reflecting surfaces and further encourage even distribution of any ...

https://en.wikipedia.org/wiki/Reverberation_room

The ratio of stress and speed should not be called "acoustic impedance" (in analogy to the mechanical impedance) because this ... One can always test for nonlinear behavior by checking for a dependence of the resonance parameters on the driving voltage. If ... Synonymous terms are "surface impedance" and "acoustic load." The load impedance is in general not equal to the material ... The transformer acts as an impedance converter in the sense that a mechanical impedance, Zm, appears as an electrical impedance ...

https://en.wikipedia.org/wiki/Quartz_crystal_microbalance

... hearing tests MeSH E01.370.382.375.050 - acoustic impedance tests MeSH E01.370.382.375.060 - audiometry MeSH E01.370.382.375. ... impedance MeSH E01.370.370.610.610.200 - cardiography, impedance MeSH E01.370.370.750 - tilt-table test MeSH E01.370.372.200 - ... intradermal tests MeSH E01.370.750.300.400 - kveim test MeSH E01.370.750.300.750 - skin test end-point titration MeSH E01.370. ... intradermal tests MeSH E01.450.495.750.300.540 - kveim test MeSH E01.450.495.750.300.750 - skin test end-point titration MeSH ...

https://en.wikipedia.org/wiki/List_of_MeSH_codes_(E01)

However, due to the general equality in acoustic impedance for many types of structures in the breast ultrasound imaging ... DATG is not a test that directly substitutes for other tests, but stands in relation to them as a technique that provides a ... The angiothermography is not a test that substitutes for other tests, but stands in relation to them as a technique that gives ... As such, it has been most successfully employed in combination with other tests to improve the quality of the diagnosis. ...

https://en.wikipedia.org/wiki/Dynamic_angiothermography

Acoustic impedance varies by rock type and can therefore be correlated to rock properties using rock physics relationships ... These blind-well mode inversions test the reliability of the constrained inversion and remove potential bias. This statistical ... Seismic surveys measure acoustic impedance contrasts between rock layers. As different geologic structures are encountered, the ... Geostatistical inversion simultaneously inverts for impedance and discrete properties types, and other petrophysical properties ...

https://en.wikipedia.org/wiki/Reservoir_modeling

This acoustic impedance log is combined with the velocity data to generate a reflection coefficient series in time. This series ... It can also be used either to test possible interpretation models for 2D and 3D seismic data or to model the response of the ... This information is then used to calculate the variation in acoustic impedance down the well bore using the Zoeppritz equations ... It may also be used to test out different geometries of structures such as salt diapirs, to see which gives the best match to ...

https://en.wikipedia.org/wiki/Synthetic_seismogram

Wave vector, wave impedance, and direction of power flow are universal. By understanding how permittivity and permeability ... This was followed by an analysis of acoustic cloaking, and whether or not coordinate transformations could be applied to ... In 2012, researchers held an experimental field-test in France, with the aim to highlight analogy with phononic crystal. ... It has been demonstrated mathematically that the 2D Maxwell equations with normal incidence apply to 2D acoustic equations when ...

https://en.wikipedia.org/wiki/Seismic_metamaterial

Brånemark sought an acoustic way to evaluate osseointegration. A patient with implants in the jaws was fitted with a bone ... When tested, the patient experienced very loud sound even at low stimulation levels, indicating sound could propagate very well ... The hearing instrument is impedance-matched. Osseointegration has been defined as the direct contact between living bone and an ...

https://en.wikipedia.org/wiki/Bone_anchored_hearing_aid

Acoustic emission Acoustic holography Acoustic impedance Acoustic interferometer Acoustic levitation Acoustic location Acoustic ... Accelerator Test Facility (New York) Accelerator mass spectrometry Accelerator physics Accelerometer Acceleron Acceptor ( ... lubrication Acoustic metamaterials Acoustic metric Acoustic microscopy Acoustic mirror Acoustic network Acoustic ohm Acoustic ... Acoustic analogy Acoustic approximation Acoustic attenuation Acoustic cleaning Acoustic cloak Acoustic contrast factor Acoustic ...

https://en.wikipedia.org/wiki/Index_of_physics_articles_(A)

The main reason for this is the difficulty of achieving proper impedance matching between the acoustic impedance of the drive ... as it also depends on the directivity of the driver being tested and the acoustic environment in front of the actual ... This improves the acoustic-electro/mechanical impedance match between the driver and ambient air, increasing efficiency, and ... The horn also improves impedance matching between the voice and the air, which produces more acoustic power for a given speaker ...

https://en.wikipedia.org/wiki/Loudspeaker

TMD fails to provide accurate estimates of ICP mostly because the acoustic impedance and its changes due to the acoustic reflex ... OAE is used in clinical practice to test for hearing deficits in babies and children who are too young to cooperate. The ... depend not only on the initial position of stapes but also on numerous other factors that affect the acoustic impedance ( ... multivariate methods have been proposed that derive ICP by combining the transit times with measured acoustic impedance, ...

https://en.wikipedia.org/wiki/Non-invasive_intracranial_pressure_measurement_methods

This test achieved its goal because it successfully verified a negative index of refraction.[1][33][35][36][37][38][39] ... Since the flow of energy remains the same in both materials (media), the impedance of the NIM matches the RHM. Hence, the sign ... Thus, the "new" metamaterial was tested for the effects described by Victor Veselago 30 years earlier. Studies of this ... to experimentally test for negative refractive index. The experiment used a waveguide to help transmit the proper frequency and ...

https://en.wikipedia.org/wiki/Negative-index_metamaterial

... scape is the component of the acoustic environment that can be perceived by humans. The acoustic environment is the ... Audio Check: a free collection of audio tests and test tones playable on-line ... In human physiology and psychology, sound is the reception of such waves and their perception by the brain.[1] Only acoustic ... Sound impedance. *Sound intensity level. *Sound power. *Sound power level. General. *Acoustic theory ...

https://en.wikipedia.org/wiki/Sound_wave

Specifically, sound is reflected anywhere where there are acoustic impedance changes in the body: e.g. blood cells in blood ... Quantitative ultrasound is an adjunct musculoskeletal test for myopathic disease in children;[13][14] estimates of lean body ... is lost from acoustic absorption. (See also Acoustic attenuation for further details on modeling of acoustic attenuation and ... The greater the difference between acoustic impedances, the larger the echo is. If the pulse hits gases or solids, the density ...

https://en.m.wikipedia.org/wiki/Medical_ultrasonography

Some pictures of acoustic recording sessions show horns wrapped with tape to help mute these resonances. Even an acoustic ... However, in the 1950s the BBC determined in a series of tests that only 20-25 dB is required for the impression of full stereo ... Also, a folded horn with an exponential taper was constructed inside the cabinet to provide better impedance matching to the ... Acoustic recording[edit]. Early recordings were made entirely acoustically, the sound being collected by a horn and piped to a ...

https://en.wikipedia.org/wiki/Phonograph_record

Testing for Mine Gases and system of Mine Signaling 1889. Cowper, Edward AlfredEdward Alfred Cowper[2] Inventor Writing ... Matched impedance principle in electro-mechanical devices 1959. Wolff, IrvingIrving Wolff[12] Engenharia Contributions to radio ... Acoustic quadrupole theory of aerodynamic noise generation 1976. Lederman, LeonLeon Lederman[14] Física Leadership in forefront ...

https://pt.wikipedia.org/wiki/Medalha_Elliott_Cresson

These garments alternate layers of materials with high and low acoustic impedance (the product of a material's density and a ... For people who are at especially high risk of developing infections, the sputum can be cultured to test for the presence of ... Computed tomography (CT scanning) is a more sensitive test for pulmonary contusion, and it can identify abdominal, chest, or ...

https://en.wikipedia.org/wiki/Pulmonary_contusion

Triple test. Quad test. Percutaneous umbilical cord blood sampling. Apt test. Kleihauer-Betke test. Lung maturity. Lecithin- ... Acoustic rhinometry. sinus. Sinusotomy. larynx. Laryngoscopy. Laryngectomy. Laryngotomy Thyrotomy. Laryngotracheal ... Cardiac stress test Bruce protocol. Electrophysiology study. Cardiac imaging. Angiocardiography. Echocardiography TTE. TEE. ... tests and. procedures. Electrophysiology. Electrocardiography Vectorcardiography. Holter monitor. Implantable loop recorder. ...

https://en.wikipedia.org/wiki/Resection_

Characteristic specific acoustic impedance. z0 (Pa·s/m) 35. 351.88. 1.1455. 403.2 ... J. Krautkrämer and H. Krautkrämer (1990), Ultrasonic testing of materials, 4th fully revised edition, Springer-Verlag, Berlin, ... Acoustic Properties of Various Materials Including the Speed of Sound. *Technical Guides - Speed of Sound in Pure Water ( ... In the 1862 American Civil War Battle of Iuka, an acoustic shadow, believed to have been enhanced by a northeast wind, kept two ...

https://en.wikipedia.org/wiki/Subsonic_speed

Ag(s) , AgCl(s) , KCl(aq) ,, 1×10−7M H+ solution ,, glass membrane ,, Test Solution ,, junction ,, KCl(aq) , AgCl(s) , Ag(s). ... Therefore, the glass electrode can be used only with a high input-impedance measuring device like a pH meter, or, more ... Glass electrode ,, Reference Solution ,, Test Solution ,, Glass electrode. ... "Test Solution" (the solution whose pH must be measured). In other words, the glass membrane and the ceramic junction occupies ...

https://en.wikipedia.org/wiki/PH_glass_electrode

Acoustic rhinometry. sinus. Sinusotomy. larynx. Laryngoscopy. Laryngectomy. Laryngotomy Thyrotomy. Laryngotracheal ... Cardiac stress test Bruce protocol. Electrophysiology study. Cardiac imaging. Angiocardiography. Echocardiography TTE. TEE. ... Impedance threshold device. *Slow code. *Lazarus syndrome, spontaneous autoresuscitation where attempts at artificial ... tests and. procedures. Electrophysiology. Electrocardiography Vectorcardiography. Holter monitor. Implantable loop recorder. ...

https://en.wikipedia.org/wiki/Cardiopulmonary_resuscitation

A path of reflected sound waves in a multilayered structure can be defined by an input acoustic impedance (ultrasound sound ... Scintigraphy ("scint") is a form of diagnostic test wherein radioisotopes are taken internally, for example intravenously or ... Acoustic Radiation Force Impulse imaging (ARFI), Supersonic Shear Imaging (SSI), and Transient Elastography.[15] In the last ...

https://en.m.wikipedia.org/wiki/Imaging_studies

... the middle ear works as an impedance equalizer between the outside air's low impedance and the cochlear fluid's high impedance ... The most widely used test for self-awareness in animals is the mirror test, in which a temporary dye is placed on an animal's ... Signal masking is when other similar sounds (conspecific sounds) interfere with the original acoustic sound.[33] In larger ... While this particular study has not been repeated since then, dolphins have since "passed" the mirror test.[43] ...

https://en.wikipedia.org/wiki/Toothed_whale

The initial auditory signal is compared with visual information - primarily lip movement - to extract acoustic cues and ... testing how much darker a computer screen can get before the viewer actually notices). The study of perception gave rise to the ... impedance matching), and the inner ear which produces neural signals in response to the sound. By the ascending auditory ... There is still active debate about the extent to which perception is an active process of hypothesis testing, analogous to ...

https://en.m.wikipedia.org/wiki/Perceptual

Tests were made at five spacing distances h/δ from the orifice. Two scaling laws were used: the Strouhal number was graphed as ... An arbitrary constant β was used to represent the impedance at the junction of the side branch with the duct. n was an integer ... Brun, E.; Boucher, R. M. G. (1957). "Research on the Acoustic Air‐Jet Generator: A New Development". The Journal of the ... In these tests the jet width was sufficient to keep the vortex shedding coherent across it. On an airfoil there would be a ...

https://en.wikipedia.org/wiki/Physics_of_whistles

... can be sometimes used as replacement for water in ultrasonic testing, as it has favourably higher acoustic impedance ( ... Acoustic Properties for Liquids. nde-ed.org *^ Formula E uses pollution-free glycerine to charge cars. fiaformulae.com. 13 ... On 4 May 2007, the US Food and Drug Administration advised all US makers of medicines to test all batches of glycerol for the ... "FDA Advises Manufacturers to Test Glycerin for Possible Contamination". U.S. Food and Drug Administration. 4 May 2007. ...

https://en.m.wikipedia.org/wiki/Glycerol

Dynamic Performance Testing of Digital Audio D/A Converters. *Fundamental theorem of analog circuits: a minimum level of power ... The signal and the noise must be measured the same way, for example as voltages across the same impedance. The root mean ... Defining and Testing Dynamic Parameters in High-Speed ADCs - Maxim Integrated Products Application note 728 ...

https://en.wikipedia.org/wiki/Signal-to-noise_ratio

... that manufacturers provide the testing laboratory with correction factors to allow laboratory electrical and acoustic testing ... All speakers should be connected in a series-parallel network, to achieve in-phase operation and impedance matching the ... Ltd, Acoustic Research Labs Pty. "Acoustic Research Labs Pty Ltd". www.acousticresearch.com.au.. ... Ltd, Acoustic Research Labs Pty. "Acoustic Research Labs Pty Ltd". www.acousticresearch.com.au.. ...

https://en.wikipedia.org/wiki/Sound_level_meter

The tests are often used in conjunction with other tests such as MRI, MRA, carotid duplex ultrasound and CT scans. The tests ... It could be presumed that each arm of the vascular system represents a single viscoelastic tube terminated by impedance, ... These modes of medical imaging conduct a spectral analysis of the acoustic signals they receive and can therefore be classified ... The tests are possibly useful for perioperative monitoring and meningeal infection.[1] The equipment used for these tests is ...

https://en.wikipedia.org/wiki/Transcranial_doppler

... tests[edit]. Main articles: Hearing test and Audiometry. Hearing can be measured by behavioral tests using an ... One way this is done is through environmental modifications such as acoustic quieting, which may be achieved with as basic a ... The purpose of the middle ear ossicles is to overcome the impedance mismatch between air waves and cochlear waves, by providing ... Such tests include auditory brainstem evoked potentials (ABR), otoacoustic emissions (OAE) and electrocochleography (ECochG). ...

https://en.wikipedia.org/wiki/Hearing

... converts the high impedance signal of the piezoelectric material into a voltage signal with a low impedance of typically 100 Ω ... Wilson, Jon S.; Ball, Stuart; Huddleston, Creed (2008). Test and Measurement: Know It All. Newnes. p. 103. ISBN 978-1856175302. ... A low impedance signal is advantageous because it can be transmitted across long cable lengths without a loss of signal quality ... It characterises a technical standard for piezoelectric sensors which contain built-in impedance conversion electronics. IEPE ...

https://en.wikipedia.org/wiki/Integrated_circuit_piezoelectric_sensor

... the middle ear works as an impedance equalizer between the outside air's low impedance and the cochlear fluid's high impedance ... "Mirror test". The New York Times. Retrieved August 3, 2015.. *^ Marten, Ken; Psarakos, Suchi (June 1995). "Using Self-View ... Signal masking is when other similar sounds (conspecific sounds) interfere with the original acoustic sound.[96] In larger ... The most widely used test for self-awareness in animals is the mirror test in which a mirror is introduced to an animal, and ...

https://en.m.wikipedia.org/wiki/Dolphins

... of Acoustic Quantities Associated with a Plane Progressive Acoustic Sound Wave NIOSH Powertools Database Sound Power Testing. ... where z0 is the characteristic specific acoustic impedance. Consequently, I = p v = p 2 z 0 , {\displaystyle I=pv={\frac {p^{2 ... The test environment can be located indoors or outdoors. The required environment is on hard ground in a large open space or ... Sound power or acoustic power is the rate at which sound energy is emitted, reflected, transmitted or received, per unit time. ...

https://en.wikipedia.org/wiki/Sound_power

Low-impedance headphones are in the range 16 to 32 ohms and high-impedance headphones are about 100-600 ohms. As the impedance ... introduce less variability when testing 6,000 and 8,000 Hz, and avoid testing issues resulting from collapsed ear canals. A ... Calibration is done with the earphones in an acoustic coupler that is intended to mimic the transfer function of the outer ear ... Their impedance varied; headphones used in telegraph and telephone work had an impedance of 75 ohms. Those used with early ...

https://en.wikipedia.org/wiki/Headphones

The central branch of the bridge has the voltage under test on one side and the calibrated voltage on the other: when they are ... Wind instruments consist of a tube which acts as an acoustic transmission line in which standing waves are set up. Open ended ... The distance of the first null from the termination depends on the nature of the terminating impedance. Nulls on transmission ... With the measurement of VSWR and the null positions the value of the terminating impedance's magnitude and phase can be ...

https://en.wikipedia.org/wiki/Null_(physics)

When a sound wave is transferred from a low-impedance medium (eg, air) to one of high impedance (eg, water), a considerable ... The primary function of the middle ear is to offset the decrease in acoustic energy that would occur if the low impedance ear ... canal air directly contacted the high-impedance cochlear fluid. ... Acoustic reflex impedance testing. This is a middle ear ... Tympanotomy impedance testing. This test measures changes in eardrum compliance because air pressure is varied in the external ...

https://emedicine.medscape.com/article/874456-overview

Acoustic impedance tests. Additional relevant MeSH terms: Hearing Loss. Deafness. Otitis Media. Otitis Media with Effusion. ... tests of absorbance for improved sensitivity in the assessment of middle-ear function including acoustic reflex testing. The ... Middle ear test [ Time Frame: Assessed at time of enrollment ]. The standard clinical middle ear test, 226 Hz tympanometry, and ... Wideband otoacoustic emission test [ Time Frame: Assessed at time of enrollment ]. An otoacoustic emission test assessed using ...

https://clinicaltrials.gov/ct2/show/NCT02019888?recr=Open&cond=%22Deafness%22&rank=13

Measured by acoustic impedance measurement. *Changes in vestibular functions [ Time Frame: Up to 4 weeks ]. Measured by ... Clinical and Genetic Testing of Patients With Usher Syndrome. The safety and scientific validity of this study is the ... MedlinePlus related topics: Genetic Testing Usher Syndrome Genetic and Rare Diseases Information Center resources: Retinitis ... Measured by electronic audiometry (ASSR test). *Changes in efficient sound transmission in the middle ear [ Time Frame: Up to 4 ...

https://clinicaltrials.gov/ct2/show/NCT03319524?term=NCT03319524&rank=1

Acoustic Impedance Tests* / methods * Adult * Ear, Middle * Hearing Loss, Conductive / etiology * Humans ... The most remarkable effects were conductive hearing loss at lower frequencies and an increase in middle-ear impedance. ...

https://pubmed.ncbi.nlm.nih.gov/24289817/

Acoustic Impedance Tests * Child * Ear, Middle / physiopathology * Environment* * Heating / adverse effects * Household ... Impedance tympanometry and the home environment in seven-year-old children J Laryngol Otol. 1990 Jan;104(1):4-8. doi: 10.1017/ ...

https://pubmed.ncbi.nlm.nih.gov/2313175/?dopt=Abstract

Chest electrical impedance tomography (EIT) is currently applied in neonatal and paediatric patients mainly within clinical ... Acoustic Impedance Tests. Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of ... These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural ... Cardiography, Impedance. A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes ...

https://www.bioportfolio.com/resources/pmarticle/2345902/Chest-electrical-impedance-tomography-measures-in-neonatology-and-paediatrics-a-survey-on.html

The secondary purpose of this test is to evaluate acoustic reflex pathways, which include cranial nerves (CN) VII and VIII and ... The primary purpose of impedance audiometry is to determine the status of the tympanic membrane and middle ear via tympanometry ... Acoustic immittance tests. The following tests are included in the category acoustic immittance tests:. * Tympanometry (most ... Acoustic reflex decay test. The acoustic reflex decay test is used to assess the integrity of CN VIII. ...

https://emedicine.medscape.com/article/1831254-overview

Acoustic Impedance Tests. Audiometry. Cochlea / abnormalities. Diagnosis, Differential. Ear / abnormalities*. Ear Ossicles / ...

http://www.biomedsearch.com/nih/Otological-aspects-earpit-deafness-syndrome/6973119.html

Acoustic Impedance Tests. Adolescent. Diagnosis, Differential. Ear, Middle / physiopathology. Eustachian Tube / physiopathology ...

http://www.biomedsearch.com/nih/Persistent-alternobaric-vertigo-at-ground/22294503.html

Acoustic impedance tests. Acquired immunodeficiency syndrome. Audiometry. Auditory evoked potentials. Brainstem auditory evoked ... acoustic reflexes, otoacoustic emissions, otoacoustic emissions suppression, and brainstem auditory evoked potential; it was ...

http://www.teses.usp.br/teses/disponiveis/5/5162/tde-02062009-092606/pt-br.php

Acoustic Impedance Tests Medicin og biovidenskab * Middle Ear Medicin og biovidenskab * Hearing Medicin og biovidenskab ...

https://vbn.aau.dk/da/publications/study-on-wideband-tympanometry-and-absorbance-within-a-danish-coh

Additional testing is often necessary.. Acoustic Immittance (also called Tympanometry or Impedance) A test that helps determine ... This test does not show whether the hearing is normal.. Toddlers. Evaluation of hearing may include the tests mentioned above ... This test is painless and takes approximately two hours. The test is either done in natural sleep (called an unsedated ABR) or ... This hearing test is typically done for infants over six months of age. This test takes advantage of a babys natural head turn ...

http://www.bcchildrens.ca/health-info/coping-support/hearing-problems/types-of-hearing-tests

... acoustic impedance explanation free. What is acoustic impedance? Meaning of acoustic impedance medical term. What does acoustic ... Looking for online definition of acoustic impedance in the Medical Dictionary? ... The acoustic impedance of bone may be nearly five times as great as that of blood. Testing middle ear acoustic impedance is ... acoustic impedance at normal incidence of fluids, acoustic impedance at oblique incidence in fluids, the Biot theory of sound ...

https://medical-dictionary.thefreedictionary.com/acoustic+impedance

Acoustic impedance. The ratio of the complex amplitude of spatially averaged acoustic pressure over a surface to the complex ... Acoustic emission. A method of nondestructive testing and materials characterization that uses mechanical waves moving through ... Acoustic radiation pressure. The net pressure exerted on a surface or interface by an acoustic wave. One might presume that the ... Acoustic interferometer. An instrument that is sensitive to the interference of two or more acoustic waves. It provides ...

https://www.accessscience.com/search?amp%3BrootID=794558&topics=Physics&start=0&%3Bstart=0&%3Bamp%3Bstart=0&%3Btopics=Paleontology&%3Btopics=Zoology&%3Bamp%3BsearchStr=Marine+ecology&types=Article&types=Video+%2F+Animation&%3Bamp%3Btopics=Earth+Science&%3Bamp%3Brows=100&rows=25

Acoustic impedance. The ratio of the complex amplitude of spatially averaged acoustic pressure over a surface to the complex ... Acoustic emission. A method of nondestructive testing and materials characterization that uses mechanical waves moving through ... Acoustic radiation pressure. The net pressure exerted on a surface or interface by an acoustic wave. One might presume that the ... The condition for which the impedance of a given electric, acoustic, or dynamic system is very high, approaching infinity. In ...

https://www.accessscience.com/search?amp%3BrootID=794558&topics=Physics&start=0&%3Bstart=0&%3Bamp%3Bstart=0&%3Btopics=Paleontology&%3Btopics=Zoology&%3Bamp%3BsearchStr=Marine+ecology&types=Article&%3Bamp%3Btopics=Earth+Science&%3Bamp%3Brows=100&rows=50

... together with an impedance tube for material sample testing. ... Acoustic Material Testing Tube Software. For measuring the ... complex acoustic impedance, complex acoustic admittance. ADDITIONAL CAPABILITIES *For tests that cannot use a material sample, ... The impedance tube, or standing wave tube, guarantees highly reproducible testing conditions. Prior to testing, the signal-to- ... or for in situ acoustic material tests, we offer a portable impedance meter system ...

https://www.bksv.com/ru-RU/products/Analysis-software/acoustic-application-software/material-testing/acoustic-material-testing-7758

Test of single degree of freedom acoustic treatment impedance models for multimodal acoustic propagation in duct with flow. ... What vestibular tests to choose in symptomatic patients after a cochlear implant? A systematic review and meta-analysis. ...

https://www.ncbi.nlm.nih.gov/pubmed?cmd=search&term=Moreau+S%5Bau%5D&dispmax=50

... speech and impedance audiometry, and acoustic reflex testing. Retrocochlear pathology can be assessed by acoustic brainstem ... tests, along with skin anergy testing, is indicated in cases in which tuberculosis is suspected. In HIV-positive patients, any ... Tests of the borders of the ulcer using Tzanck preparation, or viral cultures, help in confirming the diagnosis. Treatment of ... in a patient should prompt the physician to obtain a good history of risk factors and to perform serologic testing for HIV. ...

https://www.aafp.org/afp/1998/0415/p1813.html

Acoustic impedance testing including tympanometry and acoustic reflexes. · Speech Audiometry. · Evoked auditory assessment ... Balance Assessment including VNG, caloric and sway testing. · Rehabilitation of hearing loss including the fitting and ... The students will develop their testing techniques within Orthoptics as well as having an overview of a working Hospital Eye ...

https://www.derbyhospitals.nhs.uk/education/practice-learning-support-unit/allied-health-professions-ahp-healthcare-science/?vAction=fntDown

... paired t test). Acoustic impedance increased significantly in the corneal stiffening group after treatment (P , 0.001, paired t ... Z w is the acoustic impedance of the coupling media (i.e., saline or aqueous humor), and Z c is the acoustic impedance of the ... two sample t test). No significant change in acoustic impedance was found in the control group after PBS treatment (P = 0.10, ... between Tono-Pen readings and acoustic impedance were smaller than the corresponding slopes between GAT and acoustic impedance ...

http://iovs.arvojournals.org/article.aspx?articleid=2188466

Acoustic compliance is measured under conditions of tympanometry but the tympanometry facility is disabled during displacement ... Preferably eardrum displacement is used as a baseline measure and acoustic compliance measurement records short-term variation ... Either or both of the displacement of the eardrum when the stapedius muscle is stimulated or the aural acoustic compliance of ... Electro-acoustic impedance bridges. US4289143 *. Jan 9, 1980. Sep 15, 1981. Cselt Centro Studi E Laboratori Telecomunicazioni S ...

http://www.google.com/patents/US4841986?dq=6008737

Sequentially the individual modules are switched into a measurement circuitry for IV curves and impedance spectra, with the aim ... This work describes the design and initial test results of a field test for PV modules, where the PV modules the majority of ... N2 - This work describes the design and initial test results of a field test for PV modules, where the PV modules the majority ... AB - This work describes the design and initial test results of a field test for PV modules, where the PV modules the majority ...

https://orbit.dtu.dk/en/publications/novel-field-test-design-and-initial-result-for-ac-and-dc-characte

Acoustic impedance of the embouchure hole appears the most critical parameter. Critical variables affecting this acoustic ... Finding a particularly good example of a flute is dependent on play-testing. Head joint upgrades are usually suggested as a way ... "Acoustic impedance of the flute". Flute acoustics: an introduction. "Curved Head Student Flute by Gear4music". Gear4music. 2016 ... However, small deviations from the objective mechanical pitch (which is related to acoustic impedance of a given fingering) ...

https://en.wikipedia.org/wiki/Western_concert_flute

This standard provides specifications for instruments designed to measure acoustic impedance, acoustic admittance, or both ... The book addresses criteria for selection of pure tone and speech tests, guidelines for test administration, testing of hearing ... American National Standard Specifications for Instruments to Measure Aural Acoustic Impedance and Admittance (Aural Acoustic ... The noise test signal specified herein has been employed by the National Bureau of Standards for over 20 years in testing ...

https://www.nap.edu/read/11099/chapter/12

The dime adds acoustic impedance which would reduce the speed and efficiency of the dissipation of the vibrations. Now if there ... Thats what Id do because it should be a pretty straight forward test. ...

https://www.stereophile.com/comment/361611

Test for the middle ear is further segmented into tympanometry tests, acoustic reflex measures, and static acoustic impedance. ... On the basis of the test, the market is segmented into a test for middle ear, pure-tone test, and speech reception threshold ... test (SRT), most comfortable listening level test (MCL), uncomfortable loudness level test (UCL), speech discrimination test, ... Pure-tone test is further segmented into visual reinforcement audiometry, and conditioned play audiometry. ...

https://www.medgadget.com/2018/10/hearing-screening-and-diagnostic-devices-market-statistics-2018-2023-industry-size-growth-emerging-trends-top-companies-analysis-and-forecasts-by-mrfr.html

... using electroacoustic instrumentation and acoustic impedance equipment; to plan, conduct, habilitative and rehabilitative ... of audiometric testing protocols and test interpretations; of hearing aids and hearing aid evaluation techniques; and of aural ... of audiometric testing protocols and test interpretations; of hearing aids and hearing aid evaluation techniques; and of aural ... using electroacoustic instrumentation and acoustic impedance equipment; to plan, conduct, habilitative and rehabilitative ...

https://www.ok.gov/opm/HR_and_Employee_Services/Job_Family_Descriptors/X000_-_Health_Care_Services_and_Administration/X21_-_AUDIOLOGIST.html

Brooks, D. N. The role of the acoustic impedance bridge in impedance screening. Scandinavian Audiology,1974, 3,99-.104.Google ... Anderson, H., Barr, B., Wedenberg, E. The early detection of acoustic tumors by the stapedius reflex test. In G. Wolstenholme J ... Harper, A. Acoustic impedance as an aid to diagnosis in otology. Journal of Laryngological Otolaryngology, 1961, 75, 614-620. ... Metz, O. The acoustic impedance measured on normal and pathological ears. Acta Otolaryngologica, Supplement, 1946, 63, 1-131. ...

https://rd.springer.com/chapter/10.1007/978-1-4757-9760-2_3

are acoustic impedance of materials on either side of a boundary.. The acoustic impedance of a material is defined as the ... In the pulse-echo system, the transmitting transducer introduces a wide-band acoustic signal into the test object. The pulse ... The difference in acoustic impedance is commonly referred to as impedance mismatch. Generally the greater the impedance ... 102 g/cm2/s for the acoustic impedance. The acoustic impedance ranges from 2000. 4000 × 102 g/cm2/s for silty clay to sandy ...

https://www.hindawi.com/journals/ace/2010/508172/

https://en.wikipedia.org/wiki/Tuning_fork

The primary purpose of impedance audiometry is to determine the status of the tympanic membrane and middle ear via tympanometry. (medscape.com)
thus, the term impedance audiometry is sometimes used. (medscape.com)
Pure-tone test is further segmented into visual reinforcement audiometry, and conditioned play audiometry. (medgadget.com)
Methods A retrospective cross-sectional study was carried out with 11 patients submitted to the following procedures: anamnesis, otorhinolaryngological evaluation, tonal and vocal audiometry, acoustic immittance and brainstem auditory evoked potential (BAEP) tests. (bvsalud.org)

These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural muscle reflex elicitation). (bioportfolio.com)
The standard clinical middle ear test, 226 Hz tympanometry, and the experimental wideband middle ear tests of absorbance and admittance. (clinicaltrials.gov)
Tympanometry records changes in middle ear immittance, while air pressure is varied in the ear canal and acoustic reflexes are recorded at a single air pressure setting (ie, the pressure setting that provided the peak immittance reading for that particular ear on the tympanogram). (medscape.com)
Acoustic compliance is measured under conditions of tympanometry but the tympanometry facility is disabled during displacement measurement. (google.com)
1. A method of serially monitoring the intracranial fluid pressure of a subject which comprises alternately obtaining measurements related to the magnitude and direction of the volume displacement of an ear drum in response to induced stapedial muscle contraction and the acoustic compliance of said eardrum when pressure on opposite sides thereof is equalised by tympanometry, and using said measurements serially to monitor the intracranial fluid pressure of the subject. (google.com)
7. Apparatus as claimed in claim 6 and further comprising tympanometry means, means for obtaining a measurement related to the aural acoustic compliance of said ear drum while the latter is under the influence of the tympanometry means and transducer means for converting the acoustic wave reflected from said ear drum into an electrical signal. (google.com)
8. Apparatus as claimed in claim 7, and comprising means for alternately actuating said means for obtaining a measurement related to the ear drum displacement and said means for obtaining a measurement related to the aural acoustic compliance and for disabling the tympanometry means when the means for obtaining a measurement related to the ear drum displacement is actuated. (google.com)
Test for the middle ear is further segmented into tympanometry tests, acoustic reflex measures, and static acoustic impedance. (medgadget.com)
2. a test using tympanometry to measure how easily the tympanic membrane vibrates back and forth and at what pressure the vibration is easiest. (thefreedictionary.com)

The software helps you determine sound absorption coefficient and surface impedance by making measurements and calculations that meet the standards ISO 10534-2, ASTM E1050 - 10, and ASTM E2611 - 17. (bksv.com)
Noninvasive ultrasound measurement of acoustic impedance may be used to evaluate corneal stiffness and improve the accuracy of clinical measurements of IOP. (arvojournals.org)
The team's experimental results show that the distributed acoustic impedance measurements of a material are possible using the FSBS optoacoustic interaction, without direct interaction between light and the external material. (photonics.com)
The ATF can be used to conduct testing at cold temperatures representative of up to 45,000 ft flight altitude, while simultaneously taking Transmission Loss measurements of the chilled test sample. (sae.org)
Some investigators have found that subjective symptoms as rated by patients frequently do not correlate with rhinomanometry and acoustic rhinometry measurements (Passali et al, 2000). (aetna.com)
Their acoustic impedance is assessed by deriving the mass density from X-ray reflectometry measurements and the acoustic velocity from picosecond acoustic spectroscopy and the analysis of the frequency response of the test resonators. (upm.es)
Moreover, the acoustic pressure and sensitivity measurements showed that the manufactured transducers have central frequencies around 170 kHz with transmitted acoustic pressure between 8.9 kPa and 148 kPa, and sensitivity responses from 15.24 V/MPa to 59 V/MPa. (usp.br)
Measurements were made at different specimens with contact coupling transducers in pulse-echo testing method. (ndt.net)
The researchers demonstrated their new technique in ethanol and deionized water, taking acoustic impedance measurements, which provide information about a liquid's density and the speed of sound wave traveling through the liquid. (phys.org)
State-of-the-art normal incidence absorption measurement technology for in situ quality assurance measurements of the acoustic properties of asphalt. (bksv.com)
A lightweight, compact, robust and user-friendly system, designed for research and production quality control of road surfaces, with absorption, reflection and impedance measurements. (bksv.com)
Type 9740 is a state-of-the-art normal incidence absorption measurement system for non-destructive, in situ quality assurance measurements of the acoustic properties of ISO 10844 regulated test track asphalt according to the ISO 13472-2 test procedure. (bksv.com)
The system is based on a two-microphone, transfer-function test method, where the test system makes simultaneous measurements at all frequencies of interest while taking only a fraction of the time required by traditional, standing-wave ratio systems. (bksv.com)
It also contains all the functionality of the standard material testing software, which is a complete and fully integrated system for making acoustic measurements in the frequency range 220 Hz to 1.8 kHz with narrow-band analysis, and 250 Hz to 1.6 kHz with 1/3-octave band analysis. (bksv.com)
Ultrasonic Testing (UT) uses high frequency sound energy to conduct examinations and make measurements. (scribd.com)
As a part of NIST s program to standardize measurements of greenhouse gas emissions, we are developing long-wavelength acoustic flowmeter (LWAF) for accurate, economical measurement of flue gas flows, for example, from coal-burning power plants. (nist.gov)
Take a look at John Atkinson's 2012 bench test measurements of the Ref 150 to get a better sense for how it performs when presented with a simulated speaker load -- Graph 1 in particular. (audiogon.com)

For physiologic hearing to occur, a precochlear amplification system must be present to address the impedance mismatch that exists between air and water. (medscape.com)
If just held in open air, the sound of a tuning fork is very faint due to the acoustic impedance mismatch between the steel and air. (wikipedia.org)
Also, you should be aware that because of the significant acoustic impedance mismatch between aluminum and nonmetallic composites, you will get a large echo from the boundary even if the materials are well bonded. (ndt.net)
In cases of severe impedance mismatch that's often a more reliable test than amplitude, particularly if the composite is rough and coupling is variable. (ndt.net)
Additionally, a portion of the acoustic energy generated by the impacts during testing will be lost due to the mismatch in acoustic impedance between concrete and air. (iastate.edu)

Imaging fast electrical activity in the brain during ictal epileptiform discharges with electrical impedance tomography. (bioportfolio.com)
Electrical Impedance Tomography (EIT) is an emerging medical imaging technique which can produce tomographic images of internal impedance changes within an object using non-penetrating surface electro. (bioportfolio.com)
Detection of Vesicoureteral Reflux using Electrical Impedance Tomography. (bioportfolio.com)
The purpose of this study is to detect vesicoureteral reflux (VUR) non-invasively using electrical impedance tomography (EIT). (bioportfolio.com)
Regional pulmonary effects of bronchoalveolar lavage procedure determined by electrical impedance tomography. (bioportfolio.com)
Three-dimensional Electrical Impedance Tomography With Multiplicative Regularization. (bioportfolio.com)
The multiplicative regularization scheme is applied to three-dimensional electrical impedance tomography (EIT) image reconstruction problem to alleviate its ill-posedness. (bioportfolio.com)
Bi-frequency symmetry difference electrical impedance tomography - a novel technique for perturbation detection in static scenes. (bioportfolio.com)
A novel method for the imaging of static scenes using Electrical Impedance Tomography (EIT) is reported with implementation and validation using numerical and phantom models. (bioportfolio.com)
The goal of this feasibility study is to evaluate the ability of Electrical Impedance Tomography (EIT) for providing regional and quantitative information about the extent and nature of br. (bioportfolio.com)
The purpose of this study is to evaluate the Genesis Electrical Impedance Tomography (EIT) imaging system for use in pediatric respiratory disease populations including neuromuscular and b. (bioportfolio.com)
For functional imaging, Electrical Impedance Tomography (EIT) is a recent imaging technique to continuously monitor pulmonary functions at the bedside in ICUs. (usp.br)

4.7 Procedure B is applicable to a concrete plate resting on a subgrade of soil, gravel, permeable asphalt concrete, or lean portland cement concrete provided there is sufficient difference in acoustic impedance 3 between the concrete and subgrade or there are enough air voids at the interface to produce measurable reflections. (astm.org)
The ultrasonic diagnostic apparatus radiates an ultrasonic wave generated from an ultrasonic transducer built in an ultrasonic probe into a subject, and receives a reflected wave caused by a difference in acoustic impedance of the subject tissue by the ultrasonic probe. (google.com)

Thus by pressing the tuning fork's base against a sound board such as a wooden box, table top, or bridge of a musical instrument, this small motion, but which is at a high acoustic pressure (thus a very high acoustic impedance), is partly converted into audible sound in air which involves a much greater motion (particle velocity) at a relatively low pressure (thus low acoustic impedance). (wikipedia.org)
My guess is it does allow some of this signal to pass into the water inside, but probably only a small amount because the semi-rigid bottle presents a high acoustic impedance. (physicsforums.com)

Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of sound flow through the middle ear. (bioportfolio.com)
The standard clinical middle ear muscle reflex test assessed with 226 Hz admittance changes, and the experimental wideband middle ear muscle reflex test assessed with wideband admittance and absorbance changes. (clinicaltrials.gov)
The acoustic characteristics of materials are determined in terms of absorption, reflection, impedance, and admittance, including transmission loss. (bksv.com)

Impedance : 6 ohms nominal Terminals : gold-plated 2-way binding posts bi-wired. (audiogon.com)
In fact, if the 4 ohm tap produces the lowest output impedance, just use it regardless of the speaker's impedance characteristics (nominal or varying). (audiogon.com)
As I also mentioned, the Ref 150, like many tube amps has 3 output taps (4, 8 and 16) that are intended to correspond to the nominal impedance of the speaker. (audiogon.com)

The reciprocal of acoustic immittance is acoustic impedance. (medscape.com)
A significant change in middle ear immittance immediately after the stimulus is considered an acoustic reflex. (medscape.com)
Screening devices are further segmented into OAE/ABR testing devices, screening audiometers, immittance screeners, and others. (medgadget.com)
in the acoustic immittance test, 﫿ve patients presented with alterations, predominantly bilateral. (bvsalud.org)

The MPANLs are specified from 125 to 8000 Hz in octave and one-third octave band intervals for two audiometric testing conditions (ears covered and ears not covered) and for three test frequency ranges (125 to 8000 Hz, 250 to 8000 Hz, and 500 to 8000 Hz). (nap.edu)
Researchers at Ecole Polytechnique Fédérale de Lausanne (EPFL) observed that the hyper-frequency wave that regularly bounces off the fiber's walls creates an echo that varies, depending on the material the acoustic wave comes into contact with. (photonics.com)
Statistical Energy Analysis (SEA) has been used widely by industry and academia for more than 20 years to predict the mid-to-high frequency range behavior of complex acoustic systems. (sae.org)
All driver are in perfect working condition and have been thoroughly tested though the frequency range in our lab. (audiogon.com)
In addition to incorporating the 305mm (12in) bass driver with which AR introduced its acoustic suspension systems to home listeners, the AR-3a was the first speaker system to use two miniature hemispherical speakers developed by AR to give better midrange and high-frequency response. (audiogon.com)
305 mm (12 in) acoustic suspension woofer, 38 mm (1 1/2 in) midrange hemispherical dome, 199 mm (3/4 in) high-frequency hemispherical dome. (audiogon.com)
In the rst case, piezoelectric transducers were utilized in order to excite low frequency Lamb waves while the panel was tested under static tensile loading. (spie.org)
1.2.2 Procedure B: Impact-Echo Test- This procedure measures the frequency at which the P-wave generated by a short-duration, point impact is reflected between the parallel (opposite) surfaces of a plate. (astm.org)
Firstly, the FPGA generated waveform amplitude binary data based on direct digital frequency synthesis (DDS) technology, and then the data was converted into burst signal through an external daughter card, which included D/A conversion circuit, active low-pass filter, power amplifier circuit and impedance matching circuit. (bvsalud.org)
This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. (upm.es)
With digital recording and a transmitting voltage of about 800 V a measuring uncertainty of the ultrasonic transfer time of 0,42 µs was obtainable for a green state SSiC-specimen with a minimal thickness of 40 mm and a test frequency of 600 kHz. (ndt.net)
The aimed measuring uncertainty for a cylindrical green ceramic body with a length of 372 mm amounted to 0,27% for a test frequency of 50 kHz. (ndt.net)
In order to develop these methods the linear scattering of low frequency waves by an orifice plate have been studied, using an acoustic two-port model. (diva-portal.org)
7 In spite of patients' perception that the sounds were loud, hearing tests showed that the sounds occurred at intensities that were just barely greater than the softest sound audible at that frequency. (medical-journals.com)
In addition, the test showed that CMUT with 400 kHz frequency has wider bandwidth and better dynamic characteristics than other similar transducers. (emerald.com)
I think many tech oriented members, such as Ralph (Atmasphere), Duke (Audiokinesis) and Al (Almarg) to name a few, have written extensively about Voltage and Power Paradigm amps, and how these amps produce current and power when presented with varying speaker impedances that change as a function of frequency. (audiogon.com)
That is, this class of tube amps is able to produce output voltages that don't vary very much as speaker impedance changes as a function of frequency. (audiogon.com)
And I think our tech members mentioned that if the output tubes are presented with a stepped up impedance that is outside the optimal design range of the output tubes, the result could be higher distortion and/or loss of power delivery capability at a given frequency as a function of the speaker's impedance characteristics at that frequency. (audiogon.com)

Discontinuities in acoustic impedance are responsible for the echoes on which ultrasound imaging is based. (thefreedictionary.com)
The GAT/Tono-Pen readings, corneal stiffness (measured by ultrasound and tensile tests), and corneal thickness were compared between the two groups. (arvojournals.org)
The test results demonstrated that the output waveform reached the target with advantages of simple implementation and flexible control, the peak negative pressure generated from ultrasound transducer was doubled by means of an electrical impedance matching network. (bvsalud.org)
Test bench for development of imaging reconstruction algorithms for ultrasound t. (usp.br)
The newly developed ultrasound contrast agent has, for example, minute microbubbles formed by covering air or inert gas with carbohydrates or lipids, and the acoustic impedance of these microbubbles is equivalent to the acoustic impedance of biological tissue. (google.com)
A method and apparatus for non-destructively or non-invasively measuring a temperature change in the inside of a subject, in particular a living subject, identify the temperature change in a region of interest during the course of producing ultrasound images of the region by determining the change of the acoustic impedance of the region of interest, and allocating a temperature change to the impedance change. (google.com)

Prior to testing, the signal-to-noise ratio (SNR) can be determined at each microphone position to ensure accurate results. (bksv.com)
S] can be calculated as the ratio between the acoustic impedance [z. (thefreedictionary.com)
d] are the upstream and downstream acoustic impedance (ratio of sound pressure to volume velocity) respectively. (thefreedictionary.com)
The ratio of the complex amplitude of spatially averaged acoustic pressure over a surface to the complex amplitude of volume velocity on that surface. (accessscience.com)
sound: Impedance: For example, specific acoustic impedance (z), the ratio of acoustic pressure to particle speed, is an inherent property of the medium and of the nature of the wave. (britannica.com)
Acoustic impedance, the ratio of pressure to volume velocity, is equal to the specific acoustic impedance per unit area. (britannica.com)

The primary function of the middle ear is to offset the decrease in acoustic energy that would occur if the low impedance ear canal air directly contacted the high-impedance cochlear fluid. (medscape.com)
Current physiologic tests of auditory function in the standard clinical audiological test battery for Veterans have limited sensitivity in detecting some middle-ear disorders, and do not include a direct test of cochlear function. (clinicaltrials.gov)
The addition of WB tests of cochlear function included in the WB test battery provides an opportunity to improve audiological diagnosis of a range of hearing disorders in Veterans. (clinicaltrials.gov)
Either or both of the displacement of the eardrum when the stapedius muscle is stimulated or the aural acoustic compliance of the eardrum is measured and provided the cochlear aqueduct is open. (google.com)
Once the nerve impulse is generated in the cochlea, the signal travels along the acoustic nerve to the cochlear nuclei. (vin.com)

The secondary purpose of this test is to evaluate acoustic reflex pathways, which include cranial nerves (CN) VII and VIII and the auditory brainstem. (medscape.com)
Some of the more common complications include otitis externa, serous otitis media, Kaposi's sarcoma, eustachian tube obstruction secondary to nasopharyngeal mass, acoustic brainstem response abnormalities and sensorineural hearing loss secondary to central nervous system complications. (aafp.org)
ABR testing may be used to evaluate central nervous system pathology such as eighth cranial nerve dysfunction from vascular compression or tumors and brainstem dysfunction. (unicare.com)

6. Apparatus for serially monitoring intracranial pressure comprising means for the acoustic stimulation of a stapedial muscle, means for obtaining a measurement related to the magnitude and direction of the responsive volume displacement of the associated ear drum, means for comparing said measurement with pre-established reference data derived from the measurement of intracranial fluid pressure by other means and read-out means to display the results of said comparison. (google.com)
Acoustic stimulation methods applied during sleep in young adults can increase slow wave activity (SWA) and improve sleep-dependent memory retention. (frontiersin.org)
The aim of this study was to determine if acoustic stimulation can increase SWA and improve declarative memory in healthy older adults. (frontiersin.org)
Thirteen participants 60-84 years old completed one night of acoustic stimulation and one night of sham stimulation in random order. (frontiersin.org)
Overnight improvement in word recall was significantly greater with acoustic stimulation compared to sham and was correlated with changes in SWA between ON and OFF intervals. (frontiersin.org)
Using the phase-locked-loop method to precisely target acoustic stimulation to the upstate of sleep slow oscillations, we were able to enhance SWA and improve sleep-dependent memory storage in older adults, which strengthens the theoretical link between sleep and age-related memory integrity. (frontiersin.org)

The method, based on the reflection of an acoustic signal entered into the nasal cavity, can be used to evaluate the CSA of the nasal cavity as a function of distance from the nostril. (aetna.com)
9 single-element transducers were manufactured by using 500 kHz piezoelectric ceramic and were characterized by measuring its electrical impedance, pulse-echo response, transmitted acoustic pressure and sensitivity, through the transmission and reflection techniques. (usp.br)

Recent studies have shown promise for new wide-bandwidth (WB) tests of absorbance for improved sensitivity in the assessment of middle-ear function including acoustic reflex testing. (clinicaltrials.gov)
An acoustic reflex threshold is a middle ear measurement of stapedius muscle response to higher intensity and adequate duration sounds for individual frequencies. (medscape.com)
Consider the softest sound that elicits a reflex contraction of the stapedius muscle as the acoustic reflex threshold. (medscape.com)
Acoustic reflex thresholds generally are determined in response to stimuli of 500, 1000, 2000, and 4000 Hz. (medscape.com)
For the ipsilateral or uncrossed acoustic reflex, stimulate the ear that is monitored for response. (medscape.com)
For the contralateral or crossed acoustic reflex, present the stimulus to the ear opposite the ear that is monitored for response. (medscape.com)
The greater the hearing loss, the higher the acoustic reflex threshold for conductive hearing loss. (medscape.com)
For sensorineural hearing loss, acoustic reflex thresholds may be within the normal range, particularly for mild-to-moderate hearing losses with recruitment. (medscape.com)
Beedle, R., Hayford, E. An investigation of the relationship between the acoustic reflex growth and loudness growth in normal and pathological ears. (springer.com)
The tympanogram of sensorineural deafness also showed "A" type curve, the stapedius muscle acoustic reflex threshold could also be increased or not induced, but some patients with SHL might have loudness recruitment. (thefreedictionary.com)
According to the facial palsy protocol, tympanogram and acoustic reflex were determined as audio-logic work-up to assess the level of facial nerve lesion on at least two occasions at 3-week interval or at the most on four occasions at 12-week interval. (thefreedictionary.com)

4.4 The maximum and minimum thickness that can be measured is limited by the details of the testing apparatus (transducer response characteristics and the specific impactor). (astm.org)
This study aims to simulate and test the performance of a transmitting and receiving capacitive micro-machined ultrasonic transducer (CMUT). (emerald.com)
During final test at the factory, the transducer's unique details are measured and stored in memory, enabling the echosounder to automatically configure itself to the transducer being used. (defender.com)

Acoustic impedance of the new material is very nearly the same as water and its attenuation coefficient is lower than all other documented elastomers and many plastics. (olympus-ims.com)
Finally, the tool includes an acoustic attenuation section positioned on the body between the transmitter and the receiver. (google.ca)
The method for attenuating sonic waves generally includes transmitting a sonic wave from the transmitter to the tool, passing the sonic wave through the acoustic attenuation section, and receiving attenuated wave at the receivers. (google.ca)
8. The apparatus of claim 1 wherein the acoustic attenuation section further comprises an o-ring on the inertial mass member for sealing the fluid within the gap, and a locking cap assembly for securing inertial mass member within the cavity. (google.ca)
10. The apparatus of claim 1 wherein the acoustic attenuation section comprises three cavities, each oriented about 120 from the other two cavities. (google.ca)

This test cannot be used to directly assess auditory sensitivity, although results are interpreted in conjunction with other threshold measures. (medscape.com)
In this work, different kinds of ultrasonic dry coupling will be tested for their sensitivity and lateral resolution to detect material mismatches. (ndt.net)

Your child's audiologist will take a complete hearing history to help evaluate your child's hearing, There are many different types of hearing tests that can be used to check your child's hearing. (bcchildrens.ca)
For acoustic applications such as theaters, cinema halls, auditoriums the data on acoustic properties i.e. sound absorption coefficient and sound transmission loss are required to evaluate the acoustic behavior of panel products and to facilitate the necessary design computations. (scirp.org)
The aim of this study was to evaluate the repeatability and variability of TEOAE characteristics in hearing screening tests performed under practical conditions on normal subjects. (medscimonit.com)
The aim of this work is to develop an experimental test bench, to simulate an UST system, and to evaluate its feasibility for pulmonary functional imaging. (usp.br)
To evaluate in the diagnosis and monitoring of acoustic neuroma. (unicare.com)

acoustic impedance an expression of the opposition to passage of sound waves, being the product of the density of a substance and the velocity of sound in it. (thefreedictionary.com)
Nerve-conduction testing typically measures conduction velocity, expressed as meters/second. (nap.edu)

Nondestructive testing (NDT) is the process of inspecting, testing, or evaluating materials, components or assemblies for discontinuities, or differences in characteristics without destroying the serviceability of the part or system. (asnt.org)
These destructive tests are often used to determine the physical properties of materials such as impact resistance, ductility, yield and ultimate tensile strength, fracture toughness and fatigue strength, but discontinuities and differences in material characteristics are more effectively found by NDT. (asnt.org)
Magnetic Particle Testing uses one or more magnetic fields to locate surface and near-surface discontinuities in ferromagnetic materials. (asnt.org)

The software then calculates the acoustic properties of the material from the differences between the signals. (bksv.com)
and a controller communicatively coupled to the impedance measurement circuit and configured to calculate the impedance of a shock vector, wherein the shock vector includes a plurality of electrodes electrically connected together, and at least one other electrode, and wherein the controller calculates the impedance of the shock vector using impedances measured between the electrodes when none of them are electrically connected. (freepatentsonline.com)

In a clinical trial (n = 49) on the role of acoustic rhinometry in the diagnosis of adenoidal hypertrophy, Riechelmann et al (1999) reported that acoustic rhinometry, in general, is not suitable for assessing adenoidal size in pre-school children. (aetna.com)
Ultrasonic diagnostic methods are widely used for functional tests such as the heart and morphological diagnosis of various organs because real-time two-dimensional images can be easily observed with a simple operation by simply bringing an ultrasonic probe into contact with the body surface. (google.com)

At the time I bought these speakers, I owned a pair of Spica Angelus speakers (Stereophile Class B). I found through A/B testing that the quality and character of sound produced by the AE109s was better than the Spicas with excellent imaging characteristics. (audiogon.com)

The most remarkable effects were conductive hearing loss at lower frequencies and an increase in middle-ear impedance. (nih.gov)

Pulse-echo, phase-amplitude and amplitude-mapping approaches constitute the conceptual bases for three fundamentally different types of acoustic imaging systems and can be used for categorizing the systems. (ebooks.com)
The electrical impedance and the pulse-echo results showed frequencies below 200 kHz with amplitudes between 20 and 300 mV (peak-to-peak). (usp.br)
Firestone (1940) and Simons (1945) developed pulsed ultrasonic testing using a pulse-echo technique. (scribd.com)

The automation provided by the WB test battery could provide additional benefits in reducing the duration of the evaluation, leaving more time for evaluation of test findings and counseling. (clinicaltrials.gov)
Testing middle ear acoustic impedance is part of audiological evaluation batteries used to detect middle ear problems. (thefreedictionary.com)
The evaluation of the test bench also showed signals compatible to expected, showing the feasibility of this UST test bench for the development of reconstruction imaging algorithms. (usp.br)
Conclusion The most evident alterations in the audiological evaluation were the prevalence of the descending audiometric con﫿guration between the frequencies of 2 and 4 kHz and the absence of the acoustic re﫿ex between the frequencies of 3 and 4 kHz bilaterally. (bvsalud.org)

For automotive pass-by noise testing, this software is used to calculate the road surface sound absorption. (bksv.com)
The study was carried using acoustic pulse tester based on standing wave method for evaluating sound absorption coefficient. (scirp.org)
While there is a plenty of information on foam based absorption, there is a lack of data related to acoustic properties of wood and wood based panel products. (scirp.org)
Affixed directly to the surface of an ISO 10844 regulated test track, Type 9740 is used to measure the absorption coefficient of the asphalt without drilling a core sample according to ISO 13472-2. (bksv.com)

A method of nondestructive testing and materials characterization that uses mechanical waves moving through materials. (accessscience.com)
What Is Nondestructive Testing? (asnt.org)
It should be noted that while the medical field uses many of the same processes, the term "nondestructive testing" is generally not used to describe medical applications. (asnt.org)
The final report presents the results of an experimental and computational study on the recently-developed air-coupled impact-echo (IE) nondestructive testing (NDT) method, in which microphones replace the traditional physically-coupled IE sensors. (iastate.edu)

[ 1 ] When a sound wave is transferred from a low-impedance medium (eg, air) to one of high impedance (eg, water), a considerable amount of its energy is reflected and fails to enter the liquid. (medscape.com)
The range for acoustic reflexes in individuals with normal hearing averages 70-100 decibel (dB) sound pressure level (SPL). (medscape.com)
A test used to observe hearing behaviour to sound when the head turn test (VRA above) is not possible. (bcchildrens.ca)
A test that uses playing games in response to sound. (bcchildrens.ca)
Whether materials are intended to absorb airborne sound or reduce airborne sound transmission, the acoustic designer or acoustician needs to know the effects of the acoustic materials. (bksv.com)
This software and its associated hardware provides input to analytical and numerical tools for the prediction of the sound field in acoustic cavities such as vehicle cabins and aircraft cabins. (bksv.com)
a property of a medium computed as the product of density and sound propagation speed (characteristic acoustic impedance). (thefreedictionary.com)
Loudness as herein computed, depends upon the acoustic properties of a sound that impinges upon a normal-hearing listener. (nap.edu)
Types of testing conducted in the ATF include Transmission Loss, Sound Power, and Vibration testing. (sae.org)
Acoustic rhinometry uses a reflected sound signal to measure the cross-sectional area and volume of the nasal passage. (aetna.com)
to get the water in your bottle to vibrate a lot due to the sound from outside, you need to 'match' the impedance. (physicsforums.com)
If the bottle were put at the (narrow) end of a large, tapered acoustic horn, the pressure variations would be greater, so sound would be coupled better to the water. (physicsforums.com)
Rather than using light directly, Antman came up with the idea to use light transmitted through optical fibers to create sound waves , or acoustic vibrations, taking advantage of a phenomenon known as stimulated Brillouin scattering. (phys.org)
With these methods it is possible to capture both the complex flow, with sound generating mechanisms, and acoustic - flow interactions. (diva-portal.org)
The ANSI/ASA S12.42-2010 requires that impulse tests be performed at three ranges of impulse peak sound pressure levels. (cdc.gov)
The standard recommends generating the required impulse sound events using explosive charges or an acoustic shock tube. (cdc.gov)
Subjective tinnitus, which we refer to as tinnitus, is the false perception of sound in the absence of an acoustic stimulus. (medical-journals.com)

Preferably eardrum displacement is used as a baseline measure and acoustic compliance measurement records short-term variation, the two records being combined by computer. (google.com)
A visual depiction (e.g., a printout) of the relative compliance and impedance of the structures of the middle ear in response to pressure changes in the external ear canal. (thefreedictionary.com)
Nasal compliance was inferred by measuring nasal area by acoustic rhinometry (AR) at pressures ranging from atmospheric pressure to a negative pressure of -10 cm H2O. (aetna.com)

The provision of guidance in ventilator therapy by continuous monitoring of regional lung ventilation, aeration and respiratory system mechanics is the main clinical benefit of electrical impedance to. (bioportfolio.com)
Aetna considers rhinomanometry, acoustic rhinometry, and optical rhinometry experimental and investigational because of a lack of clinical studies demonstrating that these tests improve clinical outcomes. (aetna.com)
There is inadequate evidence of the clinical utility of rhinomanometry and acoustic rhinometry. (aetna.com)

Proper impedance matching requires the normal anatomy and functioning of an external ear and a middle ear with an intact tympanic membrane, a normal ossicular chain, and a well-ventilated tympanic cavity. (medscape.com)
a graphic representation of the acoustic impedance and air pressure of the middle ear and the mobility of the tympanic membrane, measured as part of the audiological test battery. (thefreedictionary.com)

For screening purposes, or for a general check of the pathway's integrity, usually test at 1000 Hz. (medscape.com)
Global hearing screening and diagnostic devices market has been segmented on the basis of product, indications, and test. (medgadget.com)
TEOAE-based tests can be useful tools for hearing screening. (medscimonit.com)

The non-destructive characterisation methods, especially the ultrasonic testing, to measure fast and with low costs thee inhomogeniousities and different material properties, are very interesting. (ndt.net)
The main point of this work is the optimisation of different ultrasonic testing methods for the testing of green ceramic bodies. (ndt.net)

The impedance tube, or standing wave tube, guarantees highly reproducible testing conditions. (bksv.com)

According to researchers, the acoustic impedances of water and ethanol obtained by their technique agree well with the reported standard values. (photonics.com)

Pallanch et al (1998) stated that there are many objective test values where some patients will complain of obstruction but others will not. (aetna.com)

An instrument that is sensitive to the interference of two or more acoustic waves. (accessscience.com)
LAUSANNE, Switzerland, July 31, 2018 - Forward stimulated Brillouin scattering (FSBS), because of its resonating transverse acoustic waves, has the potential to facilitate detections in an optical fiber's surroundings. (photonics.com)
oem7110, Whenever acoustic waves pass from one medium to another there is what is called an "acoustic impedance" that determines the efficiency of the transfer of wave energy. (physicsforums.com)
In your example the acoustic waves in the air arrive at the plastic bottle and impart their energy onto its surface. (physicsforums.com)
The new approach works by using optical waves that are intense enough to create an acoustic vibration that reaches outside of the fiber. (phys.org)
By treating the outer surface in a way that would attract the chemical of interest, the researchers theorize that the acoustic waves would be modified in a detectable way when the target chemical attaches to the fiber. (phys.org)

ABR and OAE testing are noninvasive methods used to detect hearing disorders. (unicare.com)

Rhinomanometry and acoustic rhinometry are objective tests that have been attempted to assess nasal airway patency. (aetna.com)
The Abdomen, Adult Echocardiography, Obstetrics and Gynecology, Sonography Principles & Instrumentation, and Vascular Technology Examinations are quite simply an objective assessment of a test taker's requisite foundation of knowledge and skills. (mometrix.com)

Alterations in vestibular examinations occurred in 90% of patients, mostly in the caloric test, with a predominance of deficient central vestibular system dysfunction. (bvsalud.org)

therefore, acoustic reflexes generally are not tested in these ears. (medscape.com)

If no middle ear were present, only 0.1% of the acoustic wave energy traveling through air would enter the fluid of the cochlea and 99.9% would be reflected. (medscape.com)
The major function of the middle ear is to match relatively low impedance airborne sounds to the higher impedance fluid of the inner ear. (vin.com)

The net pressure exerted on a surface or interface by an acoustic wave. (accessscience.com)
Acoustic rhinometry gives an anatomic description of a nasal passage, whereas rhinomanometry gives a functional measure of the pressure/flow relationships during the respiratory cycle. (aetna.com)
Passive HPDs with a non-linear valve or orifice rely on increased acoustic impedance with an increased pressure differential across the two sides of the orifice or valve. (cdc.gov)

Testing often involves stimulating a nerve at one point along its path and recording the electrical impulse from the nerve at another point. (nap.edu)
The problem is to couple the ultrasonic impulse into the testing material. (ndt.net)
In order to accurately assess the performance of these types of protectors, the American National Standards Institute revised the ANSI/ASA S12.42 (ANSI, 2010) standard to include a method to measure the impulse peak insertion loss of all hearing protectors over a wide range of impulse levels using a dual-ear acoustic test fixture and a field microphone. (cdc.gov)

This work describes the design and initial test results of a field test for PV modules, where the PV modules the majority of the time operates to produce power at their maximum power point. (dtu.dk)
All these results certify this acoustic particles focusing method can enhance the performance of hydrodynamic flow cytometer by minor modification. (bvsalud.org)
The tests can give reliable results provided that adequate procedures are used and low-noise conditions are ensured. (medscimonit.com)
The accuracy and feasibility of the air-coupled test method to determine the solid thickness of concrete structures and to detect defects or flaws, such as delaminations or voids, were verified by comparing test results obtained via the air-coupled and physically-coupled sensors. (iastate.edu)
Results obtained by these two methods are in good agreement, demonstrating the accuracy and feasibility of the air-coupled IE test method. (iastate.edu)
We put the findings together in a thorough, concise study guide that we believe allows any test taker, at any skill level, to improve his or her results dramatically with a minimum of effort . (mometrix.com)

Researchers have now demonstrated a technique to measure the distributed FSBS spectrum of an optical fiber and retrieve the local acoustic impedance of the surrounding materials. (photonics.com)
To test the technique, researchers immersed optical fibers first in water and then in alcohol, before leaving them out in the open air. (photonics.com)
Our company's name is Mometrix Test Preparation, and we have a team of standardized test researchers who have worked on developing our study guide for the ARDMS test. (mometrix.com)

Appropriate devices that allow an water immersion technique for the green ceramic testing will be demonstrated. (ndt.net)
A green ceramic step bar and a cylindrical ring with different blind holes were test specimens. (ndt.net)

Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (bioportfolio.com)
A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. (bioportfolio.com)

Along with Lamb wave testing, additional techniques were used to monitor the extent of the developed damage such as 3-dimensional Digital Image Correlation, X-ray radiography and optical microscopic analysis. (spie.org)
Nerve conduction testing also measures the amplitude of the compound action potential of a sensory nerve or the muscular wave (M wave) for a motor nerve. (nap.edu)

How to Pass the Abdomen, Adult Echocardiography, Obstetrics and Gynecology, Sonography Principles & Instrumentation, and Vascular Technology Examinations, using our easy step-by-step ARDMS Test study guide, without weeks and months of endless studying. (mometrix.com)
Our original research into the Abdomen, Adult Echocardiography, Obstetrics and Gynecology, Sonography Principles & Instrumentation, and Vascular Technology Examinations, offered by the American Registry for Diagnostic Medical Sonography (ARDMS), reveals the specific content areas and the essential skills that are critical for you to know on the ARDMS test. (mometrix.com)

This Standard specifies maximum permissible ambient noise levels (MPANLs) allowed in an audiometric test room that produce negligible masking (less than or equal to 2 dB) of test signals presented at reference equivalent threshold levels specified in American National Standard S3.6-1996 American National Standard Specification of Audiometers. (nap.edu)
The Standard is intended for use by all persons testing hearing and for distributors, installers, designers, and manufacturers of audiometric testrooms. (nap.edu)

This document does not address ABR or OAE for neurologic conditions, such as multiple sclerosis (MS), or when used as part of intra-operative monitoring (for example, during surgery for acoustic neuroma). (unicare.com)

A material sample, or coupon test, is a quick and convenient method. (bksv.com)
This Standard defines a method for computing a physical measure that is highly correlated with the intelligibility of speech as evaluated by speech perception tests given to a group of talkers and listeners. (nap.edu)
4.1 This test method may be used as a substitute for, or in conjunction with, coring to determine the thickness of slabs, pavements, decks, walls, or other plate structures. (astm.org)
4.3 This test method is a pplicable to plate-like structures with lateral dimensions at least six times the thickness. (astm.org)
4.5 This test method is not applicable to plate structures with overlays, such as a concrete bridge deck with an asphalt or portland cement concrete overlay. (astm.org)
1.1 This test method covers procedures for determining the thickness of concrete slabs, pavements, bridge decks, walls, or other plate-like structure using the impact-echo method. (astm.org)
To maintain consistency, the techniques described for each test method are those listed in the 2011 edition of ASNT's Recommended Practice No. SNT-TC-1A. (asnt.org)
Test method names often refer to the type of penetrating medium or the equipment used to perform that test. (asnt.org)
Measuring nerve conduction is a key method for testing the functioning of a peripheral nerve. (nap.edu)
To develop an optimum testing system and verify the new method, two concrete plates were tested in the laboratory, one of which was a solid concrete slab, and the other was a mock-up reinforced concrete bridge deck with artificial defects. (iastate.edu)
Finite element method (FEM) based numerical simulations were conducted using COMSOL Multi-physics software to understand the mechanics of the air-coupled IE test, determine the optimum geometry for the parabolic reflector, and investigate the effects of the microphone height. (iastate.edu)

Anatomy11

Organisms2

Diseases11

Chemicals and Drugs1

Analytical, Diagnostic and Therapeutic Techniques and Equipment11

Psychiatry and Psychology1

Phenomena and Processes5

Disciplines and Occupations1

Technology, Industry, Agriculture2

Humanities1

Information Science7

Named Groups2

Health Care3

Confirmation of deafness in infancy. (1/154)

Otolaryngological findings in congenital nasolacrimal duct obstruction and implications for prognosis. (2/154)

Tympanometry for diagnosis and treatment of otitis media in general practice. (3/154)

Behaviour and developmental effects of otitis media with effusion into the teens. (4/154)

Does early detection of otitis media with effusion prevent delayed language development? (5/154)

Auditory system: Peripheral nonlinearity and central additivity, as revealed in the human stapedius-muscle reflex. (6/154)

Practical screening priorities for hearing impairment among children in developing countries. (7/154)

Impedance analysis of the organ of corti with magnetically actuated probes. (8/154)

Acoustic Impedance Tests

Acoustics

Transducers

Electric Impedance

Ultrasonography

Plethysmography, Impedance

Cardiography, Impedance

Dielectric Spectroscopy

Hearing Disorders

Defecography

Veterans

Reflex, Acoustic

Hearing Loss

Audiometry

Cochlea

Tensor Tympani

Stapedius

Hyperacusis

Ear Ossicles

Chorda Tympani Nerve

Tympanic Membrane

Scala Tympani

Syndrome

Down Syndrome

Metabolic Syndrome X

Nephrotic Syndrome

Sjogren's Syndrome

Abnormalities, Multiple

Turner Syndrome

Search Engine

Information Storage and Retrieval

PubMed

Internet

User-Computer Interface

Software

Cochlear Aqueduct

Structure Collapse

Cerebrospinal Fluid Pressure

Pressure

Extracellular Fluid

Famous Persons

Lysobacter

Visual Field Tests

Reproducibility of Results

Visual Fields

Accidents, Home

Maple Syrup Urine Disease

Wood

Acer

Receptors, Cell Surface

Palate

Tape Recording

Confirmation of deafness in infancy. (1/154)

Otolaryngological findings in congenital nasolacrimal duct obstruction and implications for prognosis. (2/154)

Tympanometry for diagnosis and treatment of otitis media in general practice. (3/154)

Behaviour and developmental effects of otitis media with effusion into the teens. (4/154)

Does early detection of otitis media with effusion prevent delayed language development? (5/154)

Auditory system: Peripheral nonlinearity and central additivity, as revealed in the human stapedius-muscle reflex. (6/154)

Practical screening priorities for hearing impairment among children in developing countries. (7/154)

Impedance analysis of the organ of corti with magnetically actuated probes. (8/154)

Efficiently Calculating the Acoustic Transfer Impedance of a Perforate | COMSOL Blog

Tympanometry - American Family Physician

Excess Molar Volumes, Intermolecular Free Lengths, Adiabatic Compressibilities and Acoustic Impedance of Binary Mixtures of...

Deakin University / All Locations

85 of the best peer-reviewed specialists in tympanometry |TopDoctors

Search - SAE International

Thermal paper roll 57 mm wide (14 m), for medical devices | Thermal Paper | Tympanometry | evidENT Shop

Effectiveness of out-of-home day care for disadvantaged families: randomised controlled trial | The BMJ

McIntosh Applied Engineering, LLC

Patent US5728978 - Acoustic isolator for acoustic well logging tool - Google Patents

Hydrocarbons

Perturbation bandwidth effects on admittance of a typic | Open-i

product-versions-sentiero-tymp-diagnostic - PATH MEDICAL GmbH

Laird Launches Industrys Thinnest, Smallest Ceiling-Mounted Wideband Antenna

Acoustic reflex threshold financial definition of acoustic reflex threshold

Tympanometry Tests | Harley Street ENT Clinic

Tympanometry Test, Paediatric Tympanometry, Middle Ear Problem, Hearing Loss Test in Delhi, Noida, Gurugram & Patna |...

Sub-Saharan African Journal of Medicine : Table of Contents

Say What?: The Importance of the Middle Ear

Introduction to Nondestructive Testing